In recent years, expansion of the scale of networks has led to increase in the data amount and the number of network devices on a network. Accordingly, the power consumption of network devices has increased year after year. As for a technique for reducing the power consumption of network devices, i.e., a technique for realizing power saving of network devices, various techniques have been introduced. For example, there is a technique wherein a server inquires of a client under the control thereof for the next processing start point-in-time, the client which receives this informs the next processing start point-in-time, disconnects power supply while retaining a wakeup function, the server stores transmission data for the client under disconnection of power supply, and when the next processing start point-in-time comes, transmits the stored data to the client (e.g., Japanese Laid-open Patent Publication No. 2002-157053). Also, there is a technique wherein a home gateway device is allowed to perform electric control for each unit to which power is applied, to realize low power consumption (e.g., Japanese Laid-open Patent Publication No. 2002-319956). Also, there is a technique wherein when the communication amount of a network decreases, power supply for unnecessary resources is turned off while maintaining capabilities for a network (e.g., Japanese Laid-open Patent Publication No. 2010-34792).
With a network employing a technique for realizing power saving of network devices, for example, the power of a device over a communication device included in a node relating to a path or link where no communication data flows is turned off (referred to as “node device” or “node”), whereby power saving may be realized. Hereinafter, a link of which the data transmission and reception functions are stopped due to power supply for the corresponding port being turned off will be referred to as “power supply off link”. Note that a path in which the functions of all of links are stopped will be referred to as “power off path”. Also, a power off link and a power off path shall be collectively referred to as “power off section”. The power off section is in a state in which communication data is failed to be transmitted since power supply for the corresponding port was turned off.
On the other hand, along with the recent scale expansion of networks, introduction of the Generalized Multi-Protocol Label Switching (GMPLS) technology has been conceived, whereby reduction in the load up to path opening may be realized. With the GMPLS and Multi-Protocol Label Switching (MPLS) serving as base of the GMPLS, a communication route (path) called a Label Switched Path (LSP) connecting between multiple nodes is established beforehand. According to label switching employing this LSP established beforehand, data (packets) is transferred from a start point node equivalent to the initiator to a terminal point equivalent to the terminator. With the GMPLS and MPLS, at the time of establishing a path, Resource Reservation Protocol-Traffic Engineering (RSVP-TE) that is a signaling protocol for path establishment is employed. With the RSVP-TE, the start point node that requests a path establishment transmits a path setting request (called a Path Message) to the terminal point node by Hop-By-Hop, thereby performing path setting.
With a GMPLS network or MPLS network, a path is established with occurrence of a path opening request regarding a new path as a trigger. Also, a path for a detour route may be established due to a failure on a path established beforehand occurring. In the event that there is the above-mentioned power off section on a route where a path has to be set, it is desirable to resume power supply according to the power off section so as to properly perform data transmission within the power off section.
However, in general, hardware warming up time and configuration time for Field-Programmable Gate Array (FPGA) and so forth elapses until communication data can be successfully transmitted within the power off section after power is supplied to a port where power supply has been turned off. In this way, predetermined time elapses for restoration of the power off section, and accordingly, delay may occur between the path setting request to path opening at the time of a path setting request including the power off section. In particular, in the case of establishing a detour path including the power off section with occurrence of a failure as a trigger, service interruption may occur.